Warming chambers stimulate early season growth of an arctic sedge: results of a minirhizotron field study

Sullivan, Patrick F.; Welker, Jeffrey M.

doi:10.1007/s00442-004-1764-3

Cited by 80 publications

(88 citation statements)

References 48 publications

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“…Our results and those of several recent studies (Nordstroem et al 2001;Renner− malm et al 2005;Sullivan and Welker 2005;Sullivan et al 2008) clearly demon− strate that, in the hydro−terrestrial environment of wet hummock meadows, the ef− fect of passive open−top warming chambers clearly depends upon microtopography. The dry tops of hummocks have completely different microclimatic conditions in comparison with wet hummock bases.…”

Section: Microclimatic Parameterssupporting

confidence: 83%

“…Immediately following snow melt in 2002, the differences in soil surface temperatures between warmed and ambient plots approached a maxi− mum of 1.5°C. Later, daily mean temperatures differed by only 0.84°C (Sullivan and Welker 2005).…”

Section: Microclimatic Parametersmentioning

confidence: 91%

“…Temper− ature differences between hummock tops and bases reached 8-10°C in OTCs and 4-6°C in CCSs treatments. Although the ITEX warming open top chambers were used very commonly in various Arctic, Antarctic and alpine terrestrial ecosystems (Marion et al 1997;Hollister and Webber 2000;Kudo and Suzuki 2002;Wada et al 2002;Bokhorst et al 2008;Walker et al 2008;Rinnan et al 2009a;Rinnan et al 2009b;Simmons et al 2009), the OTC warming experiments are more rare in vari− ous shallow wetland habitat types (Nordstroem et al 2001;Rennermalm et al 2005;Sullivan and Welker 2005;Sullivan et al 2008). In NW Greenland wetlands (Sullivan et al 2008), the microtopography of the sites is a mosaic of hummocks, which extend above the water table, and hollows, which lie beneath 5-15 cm of wa− ter during the short growing season.…”

Section: Microclimatic Parametersmentioning

confidence: 99%

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Impact of warming on Nostoc colonies (Cyanobacteria) in a wet hummock meadow, Spitsbergen

Elster¹,

Kvíderová²,

Hájek³

et al. 2012

Polish Polar Research

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Abstract:In order to simulate the warming effects on Arctic wetlands, three passive open−top chambers (OTCs) and three control cage−like structures (CCSs) equipped with soil temperature and soil volumetric water content (VWC) probes for continuous micro− climatic measurements were installed in a wet hummock meadow, Petuniabukta, Bille− fjorden, central Spitsbergen, in 2009. The warming effects on primary productivity were investigated during summer seasons 2009 and 2010 in cyanobacterial colonies of Nostoc commune s.l., which plays an important role in the local carbon and nitrogen cycles. The microclimatic data indicated that the effect of OTCs was dependent on microtopography. During winter, two short−term snow−thaw episodes occurred, so that liquid water was available for the Nostoc communities. Because of the warming, the OTC hummock bases remained unfrozen three weeks longer in comparison to the CCSs and, in spring, the OTC hummock tops and bases exceeded 0°C several days earlier than CCS ones. Mean summer temperature differences were 1.6°C in OTC and CCS hummock tops, and 0.3°C in the OTC and CCS hummock bases. The hummock tops were drier than their bases; however the VWC difference between the OTCs and CCSs was small. Due to the only minor differ− ences in the microclimate of OTC and CCS hummock bases, where the Nostoc colonies were located, no differences in ecophysiological characteristics of Nostoc colonies ex− pressed as photochemistry parameters and nitrogenase activities were detected after two years exposition. Long−term monitoring of Nostoc ecophysiology in a manipulated envi− ronment is necessary for understanding their development under climate warming.

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Section: Microclimatic Parameterssupporting

confidence: 83%

Section: Microclimatic Parametersmentioning

confidence: 91%

Section: Microclimatic Parametersmentioning

confidence: 99%

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Impact of warming on Nostoc colonies (Cyanobacteria) in a wet hummock meadow, Spitsbergen

Elster¹,

Kvíderová²,

Hájek³

et al. 2012

Polish Polar Research

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“…Sullivan and Welker (2005) found that use of a 0.3 cm depth of field gave annual root production estimates consistent with calculations based on values in the literature for E. vaginatum (Chapin et al 1988). Therefore, a 0.3 cm depth of field was used to scale minirhizotron data in the present study.…”

Section: Minirhizotronssupporting

confidence: 83%

Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake, Alaska

et al. 2007

Self Cite

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Long-term fertilization of acidic tussock tundra has led to changes in plant species composition, increases in aboveground production and biomass and substantial losses of soil organic carbon (SOC). Root litter is an important input to SOC pools, though little is known about fine root demography in tussock tundra. In this study, we examined the response of fine root production and live standing fine root biomass to short-and long-term fertilization, as changes in fine root demography may contribute to observed declines in SOC. Live standing fine root biomass increased with long-term fertilization, while fine root production declined, reflecting replacement of the annual fine root system of Eriophorum vaginatum, with the longlived fine roots of Betula nana. Fine root production increased in fertilized plots during an unusually warm growing season, but remained unchanged in control plots, consistent with observations that B. nana shows a positive response to climate warming. Calculations based on a few simple assumptions suggest changes in fine root demography with long-term fertilization and species replacement could account for between 20 and 39% of observed declines in SOC stocks.

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“…This supports our hypothesis that E. vaginatum ecotypes have been shaped by strong selection pressures and have a very limited capacity to respond to changes in environmental conditions. A previous warming experiment at Toolik Lake observed increased leaf production of E. vaginatum in response to warming (using a similar method) but only in the early season, after which no difference in growth rate was observed between warmed and control plants (Sullivan & Welker, 2005). It is therefore possible that we would have seen differences between treatments if warming was applied earlier in the season (mid‐May).…”

Section: Discussionmentioning

confidence: 87%

Ecotypic differences in the phenology of the tundra species Eriophorum vaginatum reflect sites of origin

Parker

Tang

Clark

et al. 2017

Ecology and Evolution

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Eriophorum vaginatum is a tussock‐forming sedge that contributes significantly to the structure and primary productivity of moist acidic tussock tundra. Locally adapted populations (ecotypes) have been identified across the geographical distribution of E. vaginatum; however, little is known about how their growth and phenology differ over the course of a growing season. The growing season is short in the Arctic and therefore exerts a strong selection pressure on tundra species. This raises the hypothesis that the phenology of arctic species may be poorly adapted if the timing and length of the growing season change. Mature E. vaginatum tussocks from across a latitudinal gradient (65–70°N) were transplanted into a common garden at a central location (Toolik Lake, 68°38′N, 149°36′W) where half were warmed using open‐top chambers. Over two growing seasons (2015 and 2016), leaf length was measured weekly to track growth rates, timing of senescence, and biomass accumulation. Growth rates were similar across ecotypes and between years and were not affected by warming. However, southern populations accumulated significantly more biomass, largely because they started to senesce later. In 2016, peak biomass and senescence of most populations occurred later than in 2015, probably induced by colder weather at the beginning of the growing season in 2016, which caused a delayed start to growth. The finish was delayed as well. Differences in phenology between populations were largely retained between years, suggesting that the amount of time that these ecotypes grow has been selected by the length of the growing seasons at their respective home sites. As potential growing seasons lengthen, E. vaginatum may be unable to respond appropriately as a result of genetic control and may have reduced fitness in the rapidly warming Arctic tundra.

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Warming chambers stimulate early season growth of an arctic sedge: results of a minirhizotron field study

Cited by 80 publications

References 48 publications

Impact of warming on Nostoc colonies (Cyanobacteria) in a wet hummock meadow, Spitsbergen

Impact of warming on Nostoc colonies (Cyanobacteria) in a wet hummock meadow, Spitsbergen

Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake, Alaska

Ecotypic differences in the phenology of the tundra species Eriophorum vaginatum reflect sites of origin

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